The Houston tunnel system is a system of tunnels 6 m (about 20 ft) below Houston's downtown street system. The system is 10 km long (6-7 mi depending on the source), and forms a network of subterranean, climate-controlled, pedestrian walkways that link 95 full city blocks. Today's Tunnel is a series of underground passageways that, with above-ground skywalks, link office towers to hotels, banks, corporate and government offices, restaurants, retail stores, and the Theater District. Only one building, Wells Fargo Plaza, offers direct access from the street to the Tunnel; otherwise, other entry points are from street-level stairs, escalators, and elevators located inside buildings that are connected to the tunnel. Most of the tunnel system is located in the western half of downtown Houston.